Re: 454 Fireworks Followup


John
 

I was going to offer to send you the "same device" from a 453, only to discover that it's a 2n3441, i.e. smaller TO 66 case! (The 453 has a shunt resistor across the transistor which is either to assist self-starting or reduce device dissipation, or both).
Unusually, I can buy the 2n3442 much cheaper here in the UK, but I guess postage out to the US would bring costs back up again.
https://cpc.farnell.com/unbranded/2n3442/transistor-npn-to-3/dp/SC06770
NB your post regarding the 575 testing prompted me to put the 2N3441's test to have a look.
I have two with Tek part numbers, and two I bought about a decade ago from I know not where (now) .
With no base current they al meet the 140V spec, but the non-Tek samples have a lower "knee" (c. 90V) where collector curves head north rapidly when passing collector current. I'll try to post some photos. Not sure what the mechanism is called, but I'd say the transistors couldn't be of much use in this region, at least as linear devices.
John

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